IT201800003698A1 - LIGHTING DEVICE - Google Patents

Description

Description of the invention having as title:

"LIGHTING DEVICE"

FIELD OF APPLICATION

The present invention relates to a lighting device provided with a LED light source.

Applications of the lighting device according to the invention are for example in situations in which the emission of light from top to bottom is required, known in the sector as "down-light", and a reduced glare and high visual comfort for users is required. .

Further applications of the present invention are for example in situations in which the emission of light from the bottom up, or "up-light" is required, or for lighting devices with bracket mounting.

STATE OF THE TECHNIQUE

Lighting devices are known, for example of the spotlight type, used to illuminate specific localized areas of an environment.

A problem of known types of lighting devices is that the output light beam can cause a glare effect for the user and therefore be annoying or possibly even harmful to the eyes.

To reduce this problem, it is necessary to move the light source back with respect to the output of the support body, and at the same time reduce the emission aperture of the light beam, so as to reduce the glare effect and provide visual comfort to the user.

Some known solutions applied to light sources of the discharge lamp type provide for positioning the light source inside a tubular body, set back from an outlet opening, and using parabolas to concentrate and distribute the light beam towards the latter. .

Solutions of lighting devices are also known in which LED light sources are placed in a cavity inside a support body, spaced apart from the exit opening and parabolas are provided to convey the light beam towards the exit opening. itself. However, these solutions do not allow to obtain well-defined light cones with angles greater than 30 °.

In particular, the known solutions do not allow to obtain a wide emission, in the sector called "flood" or "medium flood", or with angles around 60 °, with a small exit opening. To achieve this, in the known art the section of the outlet opening tends to be widened, thereby leading to the problems described above.

In addition, the light beam conveyed towards the exit opening, due to the combination of the rear position of the source and the reduced section of the exit opening, is partially reflected inside the tubular body.

This involves a reduction in the emission of the light beam, and therefore a decrease in the performance of the light sources. Consequently, in order to obtain at the output a light beam having a determined emission and intensity it is necessary to use light sources having higher power, which involve an increase in energy consumption.

An object of the present invention is to provide a lighting device which allows a high efficiency of the light source and at the same time a high visual comfort for the users.

A further object of the present invention is to obtain a lighting device that has an output light beam comprised within a well-defined cone with the desired light emission and intensity.

A further object of the present invention is to provide a lighting device which allows to obtain well-defined light beams with angles equal to or greater than 30 ° to provide a lighting effect of the "flood" or "medium flood" type.

In order to obviate the drawbacks of the known art and to obtain these and further objects and advantages, the Applicant has studied, tested and implemented the present invention.

EXPOSURE OF THE FOUND

The present invention is expressed and characterized in the independent claim. The dependent claims disclose other features of the present invention or variants of the main solution idea.

In accordance with the aforementioned purposes, a lighting device according to the invention comprises:

- a support body defining a tubular cavity which extends along a longitudinal axis and is provided with a first end and a second end aligned along the longitudinal axis;

- a support element fixed to the first end of the tubular body;

- a light source of the LED (Light Emitting Diode) type installed in the tubular cavity and on the support element and configured to emit a light beam along the longitudinal axis;

- a closing element associated with the second end of the support body and provided with a through opening aligned with the longitudinal axis.

The lighting device also comprises a first lens and a second lens, spaced apart, positioned in the tubular cavity, and aligned with the aforementioned longitudinal axis.

The first lens is configured to receive the light beam from the illumination source and generate a light beam diffused towards the second lens.

The second lens is configured to receive the light beam diffused by the first lens and collimate it in a collimated beam, so as to pass it through the through aperture.

Thanks to the presence of the two lenses placed in succession one to the other, the entire light beam emitted by the light source, or at least the entire part of it that affects the first lens, is transmitted towards the exit opening and passed through it concentrating the rays within a defined emission cone. In this way, unwanted reflections of light rays inside the tubular cavity are avoided, which, on the one hand, could reduce the emission of the collimated light beam and, on the other hand, generate rays at output with angles different from those desired and potentially annoying. for users.

The two lenses placed in succession allow to obtain at the output a light beam collimated in a cone having an angle greater than or equal to 30 °, in particular between 30 ° and 70 °, without loss of light emission efficiency.

The rearward position of the light source with respect to the through-opening exit of the collimated beam, together with the reduced size of the latter, allows for a lighting device with reduced glare and high visual comfort for the user.

According to embodiments, the second lens is configured to converge the rays of the collimated beam in a focal point aligned along the longitudinal axis.

According to further embodiments, the focal point is external to the tubular cavity, so as to ensure that the entire light beam F emitted by the lighting source, or at least the portion of it that affects the first lens, is emitted through the passing aperture. . This allows to obtain a lighting device with high efficiency and therefore to limit the overall energy consumption.

According to embodiments, the section of the cone of the collimated beam at the second end of the support body is smaller than the dimension of the through opening. In this way there is no reflection of the rays of the collimated beam inside the tubular cavity and it is also guaranteed that the edges of the through opening are not illuminated, and no reflected rays are generated at the exit with unwanted angles.

ILLUSTRATION OF DRAWINGS

These and other characteristics of the present invention will become clear from the following description of embodiments, provided by way of non-limiting example, with reference to the attached drawings in which:

- fig. 1 is a sectional view of a lighting device according to embodiments of the present invention;

- fig. 2 is an exploded view of the components of the lighting device of fig. 1;

- fig. 3 is a sectional view of a lighting device according to embodiments of the present invention.

To facilitate understanding, identical reference numbers have been used wherever possible to identify identical common elements in the figures. It should be understood that elements and features of one embodiment can be conveniently incorporated into other embodiments without further specification.

DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to the various embodiments of the invention, of which one or more examples are illustrated in the attached figures. Each example is provided by way of illustration of the invention and is not intended as a limitation thereof. For example, the features illustrated or described as being part of an embodiment may be adopted on, or in association with, other embodiments to produce a further embodiment. It is understood that the present invention will include these modifications and variations.

Embodiments described with reference to figs. 1 - 3 refer to a lighting device 10, for example usable as a spotlight to illuminate an environment, or which can be integrated into a projector or similar equipment to generate a collimated light beam FC with a well-defined emission cone. The lighting device 10 can be used, for example, for “down-light” or “uplight” applications or applications with bracket mounting.

The lighting device 10 according to the present invention comprises a support body 12, defining at least part of a tubular cavity 14 which extends along a longitudinal axis X and is provided with a first end 15 and a second end 16 aligned along the axis longitudinal X.

According to embodiments, the tubular cavity 14 has a circular shape section. In particular, the tubular cavity 14 is expected to have a cylindrical shape thus avoiding the onset of unwanted reflections and deflections of light.

According to embodiments, the tubular cavity 14 has a length L and a width D.

If the section of the tubular cavity 14 has a circular shape, the width D will correspond to the diameter; if the section is polygonal, oval, or similar, the width D will correspond to the equivalent diameter D of the cross section.

According to embodiments, the width D can be constant or variable along the longitudinal axis X.

According to embodiments, the length L of the tubular cavity 14 is comprised between about 2 and about 4.5 times a width D of the tubular cavity 14 in the intermediate zone between the first lens 26 and the second lens 28.

According to other embodiments, the length L of the tubular cavity 14 is between 2.5 and 3.7 times the width D.

The lighting device 10 also comprises a support element 18 fixed to the first end 15 of the tubular body 12.

The support element 18 allows the device to be installed using suitable support means (not shown) with a desired position and possibly an orientation with respect to the area to be illuminated. The lighting apparatus 10 according to the invention also comprises a lighting source 20 of the LED type installed in the tubular cavity 14 and on the support element 18 and configured to emit a light beam along the longitudinal axis X.

The light source 20 is in particular arranged at a distance from the second end 16 of the support body 12 substantially equal to the dimension of the length L of the tubular cavity 14.

By way of example, the illumination source 20 may comprise a plurality of LEDs arranged in an orderly array on a chip.

In accordance with embodiments, the light source 20 can be defined by a point light source, or defined by a single LED.

In accordance with possible embodiments, the light source 20 can be configured to emit a light beam F having an emission angle a which can be comprised between about 90 ° and about 130 °, preferably between 100 ° and 120 °.

According to possible embodiments, the circuits necessary to power and / or drive the lighting element 20 can be housed inside the support element 18.

According to embodiments, described for example with reference to fig. 2, the lighting apparatus 10 may comprise a thermal dissipation element 19 connected to the support element 18 and configured to dissipate the heat and thermal energy generated by the lighting source 20 and the power supply circuits connected to it.

According to variants of construction, the support element 18 and the dissipation element 19 can be made in a single body. The lighting device 10 also comprises a closing element 22 associated with the second end 16 of the support body 12 and provided with a through opening 24 aligned with the longitudinal axis X.

According to possible embodiments, the closing element 22 can be made in a single body with the support body 12.

According to variant embodiments, the closing element 22 is made as a distinct and separate element from the support body 12 and can be connected to the latter in a fixed or removable way.

The support body 12, the support element 18 and the closing element 22 together define the aforementioned tubular cavity 14 which is open outwards only at the aforementioned through opening 24.

According to embodiments, the through opening 24 has a diameter D1 between about 8mm and about 12mm.

According to variant embodiments, the through opening 24 has a diameter of between about 9mm and about 11mm

According to embodiments, the width D of the tubular cavity 14 is comprised between 2 and 3 times, preferably between 2 and 2.5 times the diameter D1 of the through opening 24. This dimensional ratio has been suitably determined, to determine an emission bright that is not annoying to the user.

The lighting device 10 also comprises a first lens 26 and a second lens 28 positioned in the tubular cavity 14, aligned with the aforementioned longitudinal axis X.

The first lens 26 is directly facing the light source 20, while the second lens 28 is directly facing the through aperture 24.

The first lens 26 is configured to receive the light beam from the lighting element 20 and generate a diffused light beam FD towards the second lens 28.

The second lens 28 is configured to receive the diffused light beam FD from the first lens 26 and collimate it in a collimated beam FC in order to make it pass through the through aperture 24.

According to embodiments, the diffused light beam FD between the first lens 26 and the second lens 27 has rays R parallel to each other.

According to embodiments, the collimated beam FC generated by the second lens 28 has rays R converging to each other and substantially enclosed in a light cone having an exit angle β comprised between about 30 ° and about 70 °.

According to embodiments, the second lens 28 is configured to converge the rays of the collimated beam FC in a focal point P aligned along the longitudinal axis X.

According to further embodiments, the focal point P is placed outside the tubular cavity 14.

According to further embodiments, the dimension of the cross section S of the collimated beam FC, at the through opening 24 is smaller than the diameter D1 of the through opening 24, so that the rays of the collimated beam FC all pass through the through opening 24 without affecting the edges of the latter and therefore without being reflected in an unwanted way.

According to embodiments, the first lens 26 and the second lens 28 are both biconvex lenses with respective opposite inlet and outlet convexities.

According to embodiments, the first lens 26 and the second lens 28 are each provided with an entrance surface 26a, 28a, and an exit surface 26b, 28b, spaced apart by a maximum thickness S1, S2.

According to embodiments, the first lens 26 and the second lens 28 have respective entry convexities and exit convexities that are symmetrical to each other with respect to a transverse median plane of the lens 26, 28.

In particular, the inlet surface 26a and the outlet surface 26b of the first lens 26 have radii of curvature equal to each other and the inlet surface 28a and the outlet surface 28b of the second lens 28 have radii of curvature equal to each other.

According to variants of embodiments, the first lens 26 and the second lens 28 have respective input convexities and output convexities that are different from each other.

The radius of curvature of the first surfaces 26a, 28a and of the second surfaces 26b, 28b and the thicknesses S1, S2 of the two lenses 26, 28 can be varied according to the type and / or power of the light source 20 used, the dimensions of the tubular cavity 14, having the size of the exit opening 24 and / or the exit angle β of the collimated beam FC to be obtained.

Furthermore, the first lens 26 and the second lens 28 can be the same or different, depending on the exit angle β of the collimated beam FC to be obtained.

According to embodiments, the support body 12 comprises positioning elements 30, defining at least part of the tubular cavity 14 and configured to define a positioning of the first lens 26 and of the second lens 28 both with respect to each other and in relation to the source of lighting 20 and exit opening 24.

According to embodiments, the positioning elements 30, at least in the surface facing the tubular cavity 14, can have a matt black color and / or finish to prevent unwanted reflections of the R rays from occurring inside the tubular cavity 14.

According to possible embodiments, the finish can be achieved, for example, by anodizing or painting or other suitable methods.

According to possible embodiments, the positioning elements 30 can have an embossed surface, for example having a gloss value lower than 5.

According to possible embodiment solutions, the support element 18 is provided to close the aforementioned tubular cavity 14 by closing the first lens 26 and the second lens 28 between the positioning elements 30.

According to embodiments, the positioning elements 30 comprise a first spacer 31 placed between the light source 20 and the first lens 26, configured to position the latter at a desired distance from the light source 20.

In accordance with a possible embodiment, the light source 20 can be spaced from the first lens 26, ie with respect to a median plane of the first lens 26, by a first distance L1. By way of example only, the first distance L1 can be between 0.7 and 1.5 times the width D of the tubular cavity 14. The aforementioned reciprocal positioning between the light source 20 and the first lens 26 allows to obtain a collimated beam FC , exiting the lighting device with a very defined output cone and in which also the projection of this collimated beam FC onto a surface to be illuminated is extremely defined.

According to embodiments, the first spacer 31 can have a tubular shape with an open end 3 la, facing, in use, towards the first lens 26, and a closed end 31b, provided with a passage opening 36 in which position, in use, the light source 20.

According to embodiments, a locking element 32 can be interposed between the first spacer 31 and the first lens 26.

According to embodiments, the positioning elements 30 can comprise a second spacer 34 placed between the first lens 26 and the second lens 28 to keep them at a desired and defined mutual distance.

According to further embodiments, the positioning elements 30 comprise a third spacer 35 placed between the second lens 28 and the closing element 22.

According to possible embodied variants, for example described with reference to fig. 3, the positioning elements 30 can comprise a tubular body 38 on which the locking element 32 abuts and extending for most of the length L of the tubular cavity 14, which supports both the first lens 26 and the second lens 28.

According to embodiments, described for example with reference to figs. 1 and 2, the collimated beam FC has an exit angle β of about 60 °, and the first lens 26 and the second lens 28 are equal to each other.

According to this exemplary embodiment, the first lens 26 is placed in a first half of the length L of the tubular cavity 14 and the second lens 28 is placed in the second half of the tubular cavity 14. By way of example, the distance between the first lens 26 and the second lens 28 can be between 0.9 and 1 times the distance between the light source 20 and the first lens 26, and the distance between the second lens 28 and the through aperture 24 is between 0.7 and 0, 8 times the distance between the light source 20 and the first lens 26.

According to variants of embodiments, for example described with reference to fig. 3, the collimated beam FC has an exit angle β of about 30 °, lower than the emission angle a of the beam F coming from the light source, and the first lens 26 and the second lens 28 are different from each other.

According to this exemplary embodiment, the first lens 26 has a thickness S1 lower than the thickness S2 of the second lens 28 and the radii of curvature of the first lens 26 are lower than the radii of curvature of the second lens 28.

According to these variants, the distance between the first lens 26 and the second lens 28 can be much smaller than the distance between the light source 20 and the first lens 26.

By way of example, the distance between the first lens 26 and the second lens 28 is approximately 0.08 - 0.1 times the distance between the light source 20 and the first lens 26, and the distance between the second lens 28 and the through aperture 24 is equal to approximately 1.2-1.3 times the distance between the light source 20 and the first lens 26.

It is clear that modifications and / or additions of parts can be made to the lighting device 10 described so far, without thereby departing from the scope of the present invention.

It is also clear that, although the present invention has been described with reference to some specific examples, a person skilled in the art will certainly be able to realize many other equivalent forms of lighting device 10, having the characteristics expressed in the claims and therefore all falling within the scope of the 'scope of protection defined by them.

Claims (10)

CLAIMS 1. Lighting device comprising: - a support body (12) defining a tubular cavity (14) which extends along a longitudinal axis (X) and is provided with a first end (15) and a second end (16) aligned along said longitudinal axis (X) ; - a support element (18) fixed to said first end (15); - a lighting source (20) of the LED type installed in said tubular cavity (14) and on the support element (18) and configured to emit a light beam (F) along said longitudinal axis (X); - a closing element (22) associated with the second end (16) of the support body (12) and provided with a through opening (24) aligned to said longitudinal axis (X), characterized in that it comprises a first lens ( 26) and a second lens (28), spaced apart, positioned in said tubular cavity (14), and aligned to said longitudinal axis (X), in which said first lens (26) is configured to receive the light beam (F ) from said illumination source (20) and generate a parallel ray light beam (R) towards said second lens (28), and said second lens (28) is configured to receive the parallel ray light beam (R) from said first lens (26) and convey it in a collimated beam (FC), passing through said through opening (24). 2. Lighting device as in claim 1, characterized in that said through opening (24) has a diameter (DI) of a size comprised between about 8mm and about 12mm. 3. Lighting device as in any one of the preceding claims, characterized in that said second lens (28) is configured to converge the rays of said collimated beam (FC) in a focal point (P) aligned along said longitudinal axis (X ). 4. Lighting device as in claim 3, characterized by the fact that said focal point (P) is placed outside said tubular cavity (14). 5. Lighting device as in 2 and in any one of the preceding claims, characterized in that said collimated beam (FC) in correspondence with the through opening (24) has a cross section (S) having a dimension smaller than said diameter (DI ) of said through opening (24). 6. Lighting device as in any one of the preceding claims, characterized in that said tubular cavity (14) has a circular section and cylindrical shape. 7. Lighting device as in any one of the preceding claims, characterized in that said tubular cavity (14) has a length (L) comprised between about 2 and about 4.5 times the width (D) of said tubular cavity (14). ). 8. Lighting device as in any one of the preceding claims, characterized in that the support body (12) comprises positioning elements (30), defining at least part of the tubular cavity (14) and configured to define a mutual positioning of said first lens (26) and said second lens (28) both with respect to each other and with respect to said illumination source (20) and said exit aperture (24). 9. Lighting device as in claim 8, characterized in that said positioning elements (30) have a matt black finish. 10. Lighting device as in any one of the preceding claims, characterized in that said first lens (26) and said second lens (28) are biconvex lenses.